The present invention relates to covering equipment for use on sports arenas for protection against precipitation, which equipment comprises a driving motor, a longitudinal drum for coiling and uncoiling a covering sheet, such as a tarpaulin or plastic coversheet.
The equipment has been developed for automated covering of sports arenas, and is intended particularly for soccer fields and tennis courts.
For several decades, tarpaulins and plastic coversheet have been used for covering sports arenas to protect them against precipitation in order to avoid soaked soccer fields which rapidly turn a nice grass turf into a pool of mud. In addition, many sports arenas today have a source of heat installed in the ground, and the coversheets drawn over the surface may then be used to achieve a form of hothouse effect, with early growth of grass which gives an extended playing season.
For a long time, there have been used long steel or plastic tubes or drums of coiled cover material, which is rolled out and in again by manual power. There have gradually also been developed many different types of machinery connected to the drum to facilitate the work of covering the various playing surfaces. A feature common to all these earlier machines is that the drive of the drum is provided from a side-running machine having its own driving gear, or from some form of wires and gears on tracks.
The earlier equipment may be divided into two different, principal systems for rolling the covering material in and out. These show differences in the time it will take to roll the material in or out, and in the costs of purchasing and the installation of the equipment.
A first version, and the least expensive one, uses only one machine. Thus it is necessary to move the machine between several drums of cover material. The time it will take to cover the surface of an entire field will depend on how many rolls of material are needed due to the size of the field. A single person will be sufficient to drive the equipment.
A second version uses two machines. It will then be necessary to drive overlapping machines. This means that the machine driven as no. 2 will be laid upon the material from the first machine. This solution is somewhat more expensive than the first one, but it will be far more economical in terms of time. Furthermore, two people are needed in order to operate the equipment.
The third and new version is of the type mentioned in the introduction, which is characterized in that the casing for the driving motor is arranged so as to rotate independently relative to the elongate drum, the motor drive shaft is rigidly connected to the drum for rotation therewith, and the motor casing is fixedly connected to a reaction arm which makes contact with the ground or base surface so that, during motor operation, the casing of the driving motor remains stationary with respect to rotation while the drum is driven round.
This equipment has the advantage that it may be operated by only one person, and the coiling drum may have a considerable longitudinal extension so that only one run, or very few runs, will be necessary. This equipment will also have a relatively simple and inexpensive structural design, and it is easy to handle.
The reaction arm may advantageously be equipped with a ground contacting wheel at the distal end area thereof relative to the elongate drum.
While not strictly necessary, the driving motor may be positioned within a rigid, surrounding motor housing if the inherent rigidity in the casing for the driving motor itself is insufficient.
Further, the driving motor may include a reduction gear unit, in order that a smaller motor with lower power efficiency may be used for the equipment.
Preferably the drum may be rotatably mounted within the rotatively stationary motor housing in close proximity to the reaction arm. The transmission of power from the drive shaft to the elongate drum may take the form of an inner sleeve and an outer sleeve radially joined by a web plate where the inner sleeve is connected to the drive shaft. The drive shaft may be connected to the inner sleeve by means of a threaded expander socket coupling, and an outer sleeve may be connected to the elongate drum via bolt or rivet connections or other suitable fastening means.
Preferably a center axle may be disposed centrally along the entire longitudinal extension of the elongate drum for transmission of power from the drive shaft to the drum at more than one point along said longitudinal extension.
It is conceivable that the driving motor could well be positioned externally of the drum, but in the currently most practical embodiment of the covering equipment, the driving motor is disposed internally at one end of the elongate drum. It is also conceivable that, if the elongate drum were to have an exceedingly great longitudinal extension, another driving motor should be mounted in the drum at the opposite end thereof.